Blood pressure monitoring systems may be ambulatory or stationary. The systems employ inflatable blood pressure cuffs to obtain blood pressure measurements of patients. In operation, the blood pressure cuff is typically wrapped around a limb (typically the arm) of a patient. The blood pressure cuff is inflated to provide a certain amount of pressure on a major artery in the limb (such as the brachial artery in the arm) so as to restrict the blood flow in the artery; then the pressure is slowly released until a measurement of the systolic/diastolic pressures are obtained.
Conventional blood pressure measurement devices include those that employ a mercurial manometer with a stethoscope and those that use a sensor to detect a Korotkoff sound to determine systolic and diastolic blood pressure of the patient. Thus, the pressure readings can be determined manually by a clinician that uses a stethoscope to listen for blood flow in the artery while the cuff is slowly deflated, or the pressure readings can be obtained in an automated manner without the use of a clinician by detecting the Korotkoff sound produced from an arterial vessel of the body portion being compressed by the blood pressure cuff. One example of an automated blood pressure monitoring system that can be used during stress testing or evaluation is the Tango™ System, available from SunTech Medical Instruments, Inc., Raleigh, N.C. Other proposed automated systems are described in U.S. Pat. No. 5,660,182 to Kuroshaki et al. and U.S. Pat. No. 5,560,365 to Ogura, the contents of which are hereby incorporated by reference as if recited in full herein.
Various blood pressure cuffs have been proposed in the past. For example, the blood pressure cuffs may be bladderless, such as that proposed in U.S. Pat. No. 6,036,718 to Ledford et al., or may be configured with an internal integrated bladder as described in U.S. Pat. No. 6,245,023 to Clemmons. The contents of these patents are hereby incorporated by reference as if recited in full herein. In use, particularly for automated systems, the blood pressure cuff should be wrapped on the subject so that the sensor used to obtain the blood pressure readings is properly positioned on the patient in the appropriate location to provide adequate signal and inhibited from slipping during the evaluation.
In the past, sensors (typically microphones) of the automated systems have been positioned in a pouch located in an internal primary surface of the cuff. However, the cable that connects the sensor to the external monitoring device may move or the sensor itself may not be held in reliably snug abutment to the skin and/or over the artery of interest. In other known devices, the sensor may be adhesively positioned directly onto the skin of the patient.
Despite the blood pressure devices noted above, there remains a need to provide improved blood pressure cuffs that can be comfortably positioned on a patient and, in certain embodiments, position the sensor proximate the artery of interest and/or in a manner that can improve the signal to noise ratio in the signal(s).